Liquid fuel pumping apparatus for internal combustion engines



6, 166 K. F. HUTCHEON 3.289590 LIQUID FUEL PUMPING APPARATUS FORINTERNAL COMBUSTION ENGINES Filed Sept. 14, 1964 4 Sheets-Sheet l K. F.HuTcHEoN 3,289,590

LIQUID FUEL I UMPING APPARATUS FOR INTERNAL OMBUSTI NBS 0 ON ENGI FiledSept. 14, 1964 4 Sheets-Sham 2 Dec. 6, 1966 K F. HUTCHEON 3,239,590

LIQUID FUEL PUMPING APPARATUS FOR INTERNAL COMBUSTION ENGINES FiledSept. 14, 1964 4 Sheets-Sheet 3 Dec. 6, 1966 K. Fl HUTCHEON 3,289,590

LIQUID FUEL PING APPARATUS FOR INTERNAL BUSTION ENGINES Filed Sept. 14,1964 4 Sheets-Sheet 4 United States Patent C 3,289,590 LIQUID FUELPUMPING APPARATUS FOR INTERNAL COMBUSTION ENGINES Keith Finer Hutcheon,Gerrards Cross, England, assignor to C.A.V. Limited, London, EnglandFiled Sept. 14, 1964, Ser. No. 396,076 Claims priority, applicatlionG121; Britain, Sept. 14, 1963,

6 Claims. (Cl. 103-2) This invention relates to liquid fuel pumpingapparatus for use with internal combustion engines, and of the kindincluding an injection pump for supplying fuel to the engine in timedrelationship thereto, a feed pump for supplying fuel to the injectionpump, and an hydraulic governor for controlling the quantity of fuelsupplied by the injection pump, the setting of said governor beingdetermined by the output pressure of the feed pump.

The object of the invention is to provide such a pump in a simple andconvenient form.

According to the invention a pump of the kind specified is characterizedby the provision of a centrifugally operable relief valve forcontrolling the output pressure of the feed pump.

In the accompanying drawings:

FIGURE 1 is a sectional side elevation of one example of an apparatus inaccordance with the invention.

FIGURE 2 is a sectional view on the line 22 of FIGURE 1.

FIGURE 3 is a sectional View on the line 3-3 of FIGURE 1.

FIGURE 4 is a sectional view on the line 44 of FIGURE 1.

FIGURE 5 is an enlarged sectional side elevation of a portion of theapparatus shown in FIGURE 1.

FIGURE 6 is a sectional end view of the portion of the apparatus shownin FIGURE 5.

FIGURE 7 is a sectional end view similar to FIG- URE 6 showing amodification.

FIGURE 8 is a view similar to FIGURE 5 showing a further modification.

FIGURE 9 is a view taken on the line 9-9 of FIG- URE 8 and FIGURE 10 isa view taken on the line 10-10 of FIGURE 8.

Referring to the drawings there is provided a body part 11 in which ismounted a rotary cylindrical distributor 12. The distributor is arrangedto be driven in timed relationship with the engine 13 with which theapparatus is associated. Near one end of the distributor is formed atransverse bore 14 in which is mounted a pair of reciprocable plungers15, and the latter are arranged to be urged inwardly, as the distributorrotates, by cam lobes 16 which project inwardly from, and areequiangularly spaced about, the internal periphery of an annular ring17, there being provided a pair of guided rollers 18 intermediate theplungers and ring respectively.

Formed in the distributor is a longitudinal bore 19 which communicatesat one end with the transverse bore and which at one point is incommunication with a plurality of equi-angularly spaced radial inletpassages 20. At another point the bore 19 is in communication with a3,289,590 Patented Dec. 6, 1966 delivery passage 21 which is arranged toregister with a plurality of equi-angularly spaced delivery ports 22, inturn, as the distributor rotates. The delivery ports are incommunication respectively with injection nozzles 23 mounted to directfuel into the combustion spaces of the engine respectively. It will beseen that the number of injector nozzles is the same as the number ofengine cylinders and consequently the same as the number of inletpassages and cam lobes. In the particular example the number of enginecylinders is four, furthermore the delivery passage is disposed so as tobe in register with a delivery port during the time when the plungersare being moved inwardly so that fuel contained within the transversebore will be delivered to the engine.

At the other end of the distributor 12 is a feed pump the rotor 24 ofwhich is connected to the distributor and is arranged to be driventhereby. The feed pump has an inlet port 25 which is connected through afilter 26 with a fuel tank (not shown). The feed pump also has an outletport 27 through which fuel passes to a chamber 28 located in the bodypart.

Furthermore formed in the body part is a radially disposed cylindricalbore 29 in which is mounted a valve member 30. The latter is loaded by agovernor spring 31 in a direction towards the distributor and is urgedin the opposite direction, against the action of the spring by thepressure of fuel acting on its end remote from the spring. Fuel underpressure is delivered for this purpose from the chamber 28 through apassage 32 in the body, and a circumferential groove 33 in thedistributor. The valve member 30 is provided with a reduced portionintermediate its ends which defines a control edge 34. The edge 34controls the effective size of an inlet port 35 formed in the body partand disposed to register, in turn, with the inlet passages 20 at leastduring a portion of the time when the plungers are not being movedinwardly by the cam lobes. The annular spaces defined by the reducedportion of the valve member is in constant communication with a supplyport 36 in the body part and the latter is in constant communicationwith a supply passage 37 formed in the distributor.

Also provided in the distributor is a stepped transverse bore 38 inwhich is mounted a two part relief valve generally indicated at 39 inFIGURE 1. In the narrower end of the bore 38 is mounted a slidable part39 having a peripheral flange which can abut against the step in thebore to prevent the part falling out of the bore. In the wider end ofthe bore is mounted a further slidable part 40 having a sector shapedhead 41. Within the part 40 is formed a blind bore 42 and this cancommunicate, by a way of a port 43 with the aforesaid supply passage 37.Furthermore also formed in the further part is a further port 44 andthis co-operates with a spill port 45, formed in the disrtibutor, tocontrol the amount of fuel spilled from the chamber 28 to the pump inlet25, there being provided passages in the rotor of the feed pump and thebody part for this purpose. Moreover located intermediate the two partsis a coiled compression spring 46, the purpose of which will bedescribed, and the space between the parts is in communication with theinlet 25 of the feed pump by way of a passage 47.

In describing the operation of the apparatus it will be assumed that theengine is running at a constant speed. Starting with the distributor inthe position shown in FIGURE 1, fuel is flowing to the transverse bore14 from the feed pump via the supply passage 37, the supply port 36, theinlet port 35, one of the inlet passages and the longitudinal passagell). Fuel flowing into the transverse bore causes the plungers to bemoved outwardly and the amount of fuel flowing into the bore dependsupon the setting of the valve member and the speed of rotation of thedistributor. As the distributor further rotates from the position shownthe inlet passage 20 moves out of register with the inlet port and thedelivery of fuel to the bore ceases. As the distributor further rotatesthe delivery passage 21 registers with one of the delivery ports 22 andas soon as this occurs the plungers are moved inwardly by the effect ofthe cam lobes and fuel is expelled from the transverse bore and flowsvia the longitudinal passage, the delivery passage, and the one deliveryport to one of the injection nozzles 23 of the engine, and from thenozzle to one of the combustion spaces of the engine. Further rotationof the distributor moves the delivery passage out of register with thedelivery port and the cycle as described is repeated with fuel beingdelivered to the combustion spaces of the engine in turn. As previouslymentioned the amount of fuel delivered can be adjusted by altering thesetting of the valve member and if it is desired to increase thequantity of fuel delivered to the engine the strength of the governorspring is increased. This is achieved by moving an abutment 31a so as tocompress the spring.

The valve member also acts as a governor and for this purpose thepressure of fuel acting on the end of the valve member in opposition tothe spring is arranged to be dependent upon the speed of rotation of theengine. This is achieved by the relief valve the operation of which willbe described. If, in use, the speed of the engine rises for a givensetting of the abutment then the valve member will be moved against theaction of its spring to reduce the effective size of the delivery portand so the rise in the speed of the engine will be minimised. Converselyif the engine speed falls for the same setting of the abutment the valvemember will move to increase the effective size of the delivery port andconsequently more fuel will be delivered to the engine to minimise thereduction in speed.

As has been described the output pressure of the feed pump is applieddirectly to the valve member 30 from the chamber 28, and the supply offuel to the engine is controlled by the port 43. This port is alwaysfully open during normal operation of the pump. Moreover the port 44 andspill port are always partly in register with each other when the pumpis operating normally, and these two ports form a spill passage, theeflective size of which, and hence'the quantity of fuel spilled from thechamber 28 to the inlet of the feed pump, is dependent upon the settingof the part 40. The setting of the part 40 is dependent upon the fuelpressure acting on the part and the speed of rotation of thedistributor. As the speed of rotation of the distributor increases sothe centrifugal force acting on the head 41 increases and the part willbe urged to close the spill passage constituted by the ports 44 and 45.Acting in the opposite direction to the centrifugal force is a forceproduced by the pressure of fuel. Considering the case when the engineis running at an appreciable speed, so that the fuel pressure acting onthe outer ends of the parts urges them into contact with each otheragainst the action of the spring 46, the difference of the forces actingon the individual parts urges the parts as a single body, in a directionto oppose the centrifugal force. This is because the part 40 is oflarger diameter than the part 39, and the parts assume an equilibriumposition such that the force exerted by the fuel pressure just balancesthe centrifugal force. If the speed changes then the parts move toincrease or decrease the size of the spill passage to change the fuelressure to produce a new equilibrium position. By this means the fuelpressure is made dependent upon the square of the speed. The purpose ofthe spring 46 is to modify the speed pressure characteristic at lowspeeds since, until the fuel pressure is sufficient to move the partsinto contact with each other the spill passage remains virtually closed.

In a modification shown in FIGURE 7 the parts are joined together andconstitute a stepped part 50 the spring 46 being omitted and replaced bya pair of springs 51 mounted to act between the head of the part and thedistributor. The effect of this is to modify the speed pressurecharacteristic by making the fuel pressure higher over the whole speedrange.

As previously stated the feed pump inlet 25 is connected to a fuelsupply tank through a filter 26 and if for any reason the supply to thefeed pump is restricted then the output pressure of the feed pump willdecrease. This has an effect on the setting of the valve member 30 andthe latter will move to increase the quantity of fuel supplied to theengine with a resultant increase in the speed of the engine. Thisincrease of engine speed may result in a slight rise in the outputpressure of the feed pump but,

it has been found that this is insufficient to cause the valve member toregain control of the engine speed. The position is worsened by the factthat at high speeds the plungers 15 tend to act as a pump and themselvesdraw in fuel from the passages and spaces within the body part. Althoughthe quantity of fuel within the body part is fairly small the associatedengine may accelerate very quickly particularly if it is not loaded, anda dangerous speed may be attained before the fuel is consumed. Thepurpose of the port 43 is to prevent this happening. Should the outputpressure of the feed pump start to fall the centrifugal force will movethe part 40 in a direc tion to reduce the size of the spill passage,constituted by the ports 44, 45, in an attempt to increase the outputpressure of the feed pump however, should the pressure continue to fallthe part will move further to close the port 43 and so prevent furtherfuel being delivered to the transverse bore. It should be noted that thevalue member 30 is always exposed to the output pressure of the feedpump.

In a modified form of the relief valve, as illustrated in FIGURES 8, 9and 10, there is provided a stepped transversely disposed bore 54.Moreover formed in the distributor is a passage 55 which is tangentiallydisposed with respect to the bore and which cuts into the wider portionthereof, the passage extends through the distributor and communicateswith the chamber 28. Near the opposite end of the bore is formed anannular recess 56 which is also in communication with the chamber 28through passages 57. Furthermore intermediate the recess 56 and thepassage 55 is formed a further recess 58 which communicates with thefeed pump inlet through a passage 59.

Located in the bore is a part 60 which is formed integrally with asector shaped head 61. The part is provided with a first land 62 havinga diameter equal to that of the narrower portion of the bore and asecond land 63 having a diameter equal to that of the wider portion ofthe bore. Moreover, a third land 64 is provided to close the wider endof the bore. Furthermore diametrically opposite the point of entry ofthe passage 55 into the bore is formed a chamber 65 from which extendsthe supply passage 37. As in the modification of the previous example apair of springs 65 is provided to modify the pressure/ speedcharacteristicof the relief valve.

The operation of the relief valve is substantially as was described forthe first example and in this case the amount of fuel spilled iscontrolled by the size of the gap between the inner edge of the land 62and the adjacent edge of the recess 56. As in the previous example inthe event of the output pressure of the feed pump falling owing to aninterruption in the supply thereto the part will be moved by thecentrifugal force so that the land 63 isolates the chamber 65 from thepassage 55 and so prevents fuel being drawn from the chamber 28 by theplungers 15.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. Liquid fuel pumping apparatus for supplying fuel to an internalcombustion engine, and comprising in combination, an injection pumpwhich is arranged to be driven in timed relationship to an engine forsupplying fuel thereto, a feed pump for supplying fuel to the injectionpump, passage means connecting said feed pump to said injection pump,governor means in said passage means for controlling the amount of fuelfed by the feed pump to the injection pump, said governor means being inpart, responsive to the output pressure of the feed pump, a valve forcontrolling communication between the feed pump and said passage means,centrifugal biasing means acting to close said valve as the engine speedincreases, fluid pressure biasing means acting to open said valve with aforce dependent upon the output pressure of the feed pump, saidcentrifugal biasing means being such that at any given speed, the valvewill be moved to its closed position to shut off the supply of fuel tothe injection pump when the force of said centrifugal biasing meansexceeds the force dependent upon the output pressure of the feed pump.

2. Liquid fuel pumping apparatus for supplying fuel to an internalcombustion engine, and comprising an injection pump which is arranged tobe driven in timed relationship to the engine for supplying fuelthereto, a feed pump for supplying fuel to the injection pump, governormeans for controlling the amount of fuel fed by the feed pump to theinjection pump, said governor means being in part responsive to theoutput pressure of the feed pump, a rotary part which is arranged to bedriven at a speed dependent upon the speed at which the engine isoperating, a radial bore defined in said part, a valve member slidablewithin said bore, and arranged to be subjected to the output pressure ofthe feed pump, passage means defined in said valve member through whichfuel is fed from the feed pump to the injection pump, said valve memberbeing arranged to control the flow of fuel through said passage means, ahead mounted upon said valve member, whereby as the part rotates, aforce will be applied to the valve member to move the valve member in adirection to prevent the flow of fuel through said passage means, themovement of the valve member in this direction being resisted by theforce developed on the valve member by the pressure of fuel actingthereon.

3. Liquid fuel pumping apparatus as claimed in claim 2 in which saidfeed pump takes suction from a source of fuel at a lower pressureincluding further passage means in said valve member through which fuelunder pressure from the feed pump can fiow to said source of fuel at alower pressure, the flow of fuel through said further passage meansbeing controlled by movement of said valve member, whereby the pressureof fuel delivered by the feed pump will vary as the square of the speedat which the part rotates.

4. Liquid fuel pumping apparatus for use with internal combustionengines, and of the kind comprising in combination a body part, a rotarydistributor mounted in the body part, and adapted to be driven in timedrelationship to the engine with which the apparatus is associated, abore formed in the distributor, a reciprocable plunger slidably mountedin the bore, a cam for imparting inward movement to the plunger as thedistributor rotates, a delivery passage in communication with said bore,a delivery port in the body part, and disposed so that the deliverypassage can register therewith during the time the plunger is movedinwardly by the cam, said delivery port being adapted for connection toa combustion space of the engine, an inlet passage in the distributor incommunication with said bore, and an inlet port in the body part andwith which the inlet passage registers at least during part of the timewhen the delivery port is out of register with the delivery passage, afeed pump mounted in the body part, said feed pump having an inlet andan outlet, a hydraulic governor mounted in the body part and connectedintermediate the outlet of the feed pump and the inlet port forcontrolling the quantity of fuel delivered to the bore, the setting ofsaid governor being in part, dependent upon the pressure of fueldelivered by said feed pump, a transversely disposed drilling in thedistributor, a valve member including a port slidably mounted in saiddrilling, said valve member having a head formed on one end thereof, andarranged so that when the distributor is rotated, the centrifugal forceacting on the head of said valve member will bias the valve member inone direction, a surface being provided on the valve member againstwhich the output pressure of the feed pump acts to produce a force tooppose said centrifugal force, passage means defined in the distributorthrough which fuel from the outlet of the feed pump flows to thegovernor, said port being positioned with respect to said passage meansto control the flow of fuel through said passage means, the arrangementbeing such that in the event of the force produced by the fuel pressureacting against said surface being insufficient to balance thecentrifugal force, the valve member will move to close said port, toprevent further fuel being supplied to the engine.

5. Liquid fuel pumping apparatus as claimed in claim 4 including furtherpassage means in the distributor and body part, and through which theoutlet of the feed pump is in communication with the inlet thereof, afurther port in said valve member located with respect to said furtherpassage means in such a position that as the output pressure of the feedpump increases, more fuel will flow through said further passage meanswhereby the output pressure of the feed pump will vary as a function ofthe square of the speed at which the distributor is driven.

6. A liquid fuel pumping apparatus for use with internal combustionengines, and of the kind comprising in combination a body part, a rotarydistributor mounted in the body part and adapted to be driven in timedrelationship to the engine with which the apparatus is associated, abore formed in the distributor, a reciprocalble plunger slidably mountedin the bore, a cam for imparting inward movement to the plunger as thedistributor rotates, a delivery passage in communication with said bore,a delivery port in the body part, and disposed so that the deliverypassage can register therewith during the time the plunger is movedinwardly by the cam, said delivery port being adapted for connection toa combustion space of the engine, an inlet passage in the distributor incommunication with said bore, an inlet port in the body part and withwhich the inlet passage registers at least during a part of the timewhen the delivery port is out of register with a delivery passage, afeed pump mounted in the body part, said feed pump having an inlet andan outlet, a hydraulic governor mounted within the body part forcontrolling the quantity of fuel delivered to the bore, the setting ofsaid governor being in part dependent upon the pressure of fueldelivered by said feed pump, a transversely disposed drilling formed inthe distributor, a valve member slidably mounted in said drilling, ahead connected to one end of the valve member, said head projecting fromthe distributor and rotatable therewith within an annular chamberdefined by said distributor and said body part, said chamber being incommunication with the outlet of the feed pump, a surface being providedon the valve member against which the output pressure of the feed pumpcan act to produce a force to oppose the centrifugal force resultingfrom rotation of the head, first and second ports in the wall of saidtransversely disposed drilling, passage means in the distributor andbody part through which said first port is in communication with thegovernor, further passage means in the distributor and body 7 partthrough which said second port is in communication with the inlet of thefeed pump, first and second grooves formed on the periphery of the valvemember for registration with said first and second ports respectively,said first and second grooves being in communication with said annularchamber, the axial position of the ports and groove being such that inthe event of the output pressure of the feed pump rising for a givenspeed of the distributor, said second port Will be uncovered to agreater extent to allow fuel from the chamber to be spilled to the inletof the feed pump, and whereby in the event that the output pressure ofthe feed pump falls, the second port will be covered to a greater extentto reduce the spillage of fuel, and in the event that the fuel pressuresfalls further, the

bore.

References Cited by the Examiner UNITED STATES PATENTS Roosa 10'3-2.1

Seaver 1032.1

Hess 1032.1

Liardet 1 10-32.1 Evans 1032.1

Volossevich 103-2.1

Hutcheon 1032.1

Knudson 1032.1

Hutcheon 103-2.1

MARK NEWMAN, Primary Examiner.

first port will be closed to cut off the flow of fuel to the 15 MARTINSCHWADRON, Examiner- W. I. KRAUSS, Assistant Examiner.

1. LIQUID FUEL PUMPING APPARATUS FOR SUPPLYING FUEL TO AN INTERNAL COMBUSTION ENGINE, AND COMPRISING IN COMBINATION, AN INJECTION PUMP WHICH IS ARRANGED TO BE DRIVEN IN TIMED RELATIONSHIP TO AN ENGINE FOR SUPPLYING FUEL THERETO, A FEED PUMP FOR SUPPLYING FUEL TO THE INJECTION PUMP, PASSAGE MEANS CONNECTING SAID FEED PUMP TO SAID INJECTION PUMP, GOVERNOR MEANS IN SAID PASSAGE MEANS FOR CONTROLLING THE AMOUNT OF FUEL FED BY THE FEED PUMP TO THE INJECTION PUMP, SAID GOVERNOR MEANS BEING IN PART, RESPONSIVE TO THE OUTPUT PRESSURE OF THE FEED PUMP, A VALVE FOR CONTROLLING COMMUNICATION BETWEEN THE FEED PUMP AND SAID PASSAGE MEANS, CENTRIFUGAL BIASING MEANS ACTING TO CLOSE SAID VALVE AS THE ENGINE SPEED INCREASES, FLUID PRESSURE BIASING MEANS ACTING TO OPEN SAID VALVE WITH A FORCE DEPENDENT UPON THE OUTPUT PRESSURE OF THE FEED PUMP, SAID CENTRIFUGAL BIASING MEANS BEING SUCH THAT AT ANY GIVEN SPEED, THE VALVE WILL BE MOVED TO ITS CLOSED POSITION TO SHUT OFF THE SUPPLY OF FUEL TO THE INJECTION PUMP WHEN THE FORCE OF SAID CENTRIFUGAL BIASING MEANS EXCEEDS THE FORCE DEPENDENT UPON THE OUTPUT PRESSURE OF THE FEED PUMP. 